IRRIGATION. 



dy, and of any magnitude, it is common 

 to allow their flowing, to the depth of 

 many feet, over low lands ; so that, when 

 kept stationary fora few hours, the fecula 

 and sediment may be deposited; as is 

 often the case, to the depth of many 

 inches during a single tide ; and give a 

 new stratum of the iinest soil. See 

 WAIIPINB. 



These points must be well understood, 

 because they form a very prominent fea- 

 ture in the practice of irrigation, and 

 will be found highly worthy the notice of 

 all who lay their lands down with that in- 

 tention. But we must observe, that many 

 soils laying contiguous to streams, and 

 well situated for irrigation, are naturally 

 so rich, as not to depend on any deposit 

 from the waters for their annual produce : 

 such require but moderate watering, and, 

 in some instances, more to be sheltered 

 during the winter by complete inundation, 

 than by refreshing flows. Where such 

 prevail, the water ought to be admitted 

 only when clear, and then from the very 

 surface ; in centra-distinction to poor, or 

 dry soils, which want heart as well as 

 moisture. The fact is, that, by means of 

 an artificial supply of water, the grass 

 will shoot out far more early, which is an 

 object of the utmost importance to most 

 farmers and graziers; and the crop will 

 be much heavier than on lands not so 

 watered. But the hay from watered 

 meadows is frequently coarse, and not 

 much relished by the more delicate clas- 

 ses of cattle. However, store cattle, 

 which indeed scarcely ever refuse what- 

 ever is offered, will consume it with 

 avidity. Another objection to hy from 

 watered meadows is, that, being some- 

 times gritty, in consequence of the sedi- 

 ment deposited by muddy water, it is in 

 a measure injurious to the teeth of those 

 animals by which it is eaten. But the 

 great importance of an early bite, for at 

 least a month, in general, before other 

 pastures are sufficiently forward to re- 

 ceive cattle, is of itself such a considera- 

 tion as outweighs every objection, and 

 causes watered meadows to yield double 

 the rent given before they were subjected 

 to irrigation. In many places the grass 

 of watered meadows, from the fifteenth 

 of March to the fifteenth of May, lets 

 from twenty to twenty-five shillings per 

 acre. The crop is usually two tons, in 

 all seasons : in dry ones it is not subject 

 to the ordinary risk of being burnt up ; 

 and, not only proves highly serviceable 

 to the farmer himself, but to his neigh- 

 bours ; who thus obtain a supply of hay, 

 when their own meadows have failed. 



When land has been long watered, its 

 qualities are meliorated considerably ; 

 but this is not the work of a day ; and 

 when the adjoining lands abound with 

 coarse herbage, with water grasses espe- 

 cially, the crops will too frequently suf- 

 fer by such vicinity. It will, at first view, 

 appear strange, but it is nevertheless 

 true, that swampy lands become firmer 

 when regularly watered. In their natural 

 state the water oozes upwards, and 

 loosens the soil ; but after the proper 

 levels are found, and the catch drains 

 are laid, so as to draw off the surplus 

 water, the moisture is drawn downwards, 

 and the finer parts get into the interstices, 

 so as to compact the whole, and give a 

 firm footing, where before even a sheep 

 would have been bogged. We must, 

 however, state, that though some watered 

 meadows will bear cattle, it is by no 

 means adviseable to let any thing heavier 

 than a sheep feed upon them : the latter 

 do little injury to the ridges, and by their 

 close bite, as well as by their excellent 

 manure, cause the grass to tiller forth, 

 so as to form a close mat upon the soil. 

 Whereas when large animals are allowed 

 to tramp on the ridges, the borders of 

 the drains are in general injured; and 

 whenever, as will happen, the prints of 

 their feet are left, the soil will become 

 quaggy, and retain little pools, which in- 

 fallably sour the grass, and negative the 

 intention of watering. Herfce clay soils 

 are extremely difficult to improve by 

 this operation ; nor can such be reclaimed 

 but by a very expensive course of drain- 

 ing, manuring, and breaking into a crum- 

 bly state : certainly clay soils may be 

 formed into ridges, and grass may be 

 made to grow upon them ; but they will 

 not produce sweet herbage ; their sur- 

 faces will crack, their crops will be pre- 

 carious, and their seasons for feeding 

 must depend entirely on the dryness of 

 the weather. Hence we may, in general 

 terms, consider clay soils to be unfit for 

 irrigation ; the expense being great, and 

 the money being more likely to yield a 

 greater profit by other means; while 

 their crops and pasturage are, in various 

 points, of an inferior value. 



But to proceed : the secondary drain, 

 which supplies the whole of a field 

 through which it passes, should be inter- 

 rupted at every fall of four inches at 

 farthest, by small sluices, or penstocks, 

 and have small branch -drains cut to the 

 right and left, in such manner as may 

 cause the water to branch out into the 

 whole expanse of its level. The turf cut 

 from the surface of each drain, ought to 



